<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>示例15</title>
</head>
<body>
    <script>
        const map = new Map()
        map.set("foo",789)
        map.set("bar",true)
        map.set(undefined,404)
        for (const key of map.keys()){
            console.log(key)
        }
        for(const value of map.values()){
            console.log(value)
        }
        for(const item of map.entries()){
            console.log(item[0],item[1])
        }
    </script>
</body>
</html>